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Mechanics

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1. Mechanics
A wrecking ball of mass 250kg is being used to knock down a brick wall. The ball hits the wall at a velocity of 4m/s. After impact, if three 20kg blocks of wall move at a velocity of 2m/s and two 40kg blocks of wall move at a velocity of 3m/s, using the conservation of momentum, calculate the velocity of the wrecking ball after impact.

2. Re: Mechanics
In simple terms,

Momentum = mass x velocity

The consevation of momentum states that:
Total Momentum Before = Total Momentum After

Does this help?
3. Re: Mechanics
The total momentum before impact must be the same as the total momentum after impact.

Before impact, the only thing moving is the wrecking ball... and it's momentum is .

After impact, the wrecking ball is moving with velocity , and we also have all the bricks with their masses and velocities, so total momentum after is:

Since

We can say:

One equation, one unknown ... solve for .
4. Re: Mechanics
yh...i got the answer as v=2.56ms-1. Is this right?

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Last updated: May 6, 2012
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